1. Field of the Invention
The present invention relates generally to TM.sub.0 and TE.sub.0 cavity resonators and more particularly to such a resonantor that substantially increases the TE.sub.0 mode components, decrease the TM.sub.0 mode components and projects TE.sub.0 mode components on to a plasmatized material.
In the following description, the mode nomenclature includes a single subscript which indicates the number of spatial cycles along an orthoradial direction.
For electromagnetic waves from the ultrashort to optical range, the TE.sub.0 propagation mode is one of the most interesting modes for applications. For telecommunication purposes in circular waveguides, the TE.sub.0 mode has the least attenuation. Further, for plasma excitation, U.S. Pat. No. 4,175,830 issued Nov. 27, 1979 includes a disclosure that the TE.sub.0 mode is a plasma confining mode in the presence of a D.C. magnetic field coaxial with a TE.sub.O mode wave beam; that is, when a plasma is flashed by focusing a powerful TE.sub.0 mode wave beam on a solid material, a part of the plasma remains confined at the center of a focal spot where the plasma may reach a much higher temperature than anywhere else.
This property of confining electrons afforded by TE.sub.0 mode waves in free space may be used to provide pseudo-cathodes in electrolytes and thus store solar energy by electrochemical reactions.
On the other hand, the TM.sub.0 mode is one of the easiest to produce and filter. It is readily filtered by parallel sided plates or diopters at the Brewster's incidence angle. But the TM.sub.0 mode is not endowed with a plasma confining property except when used as a standing wave in a cavity resonator.
2. Description of the Prior Art
In U.S. Pat. No. 4,175,830 issued Nov. 27, 1979 and U.S. Pat. No. 4,235,517, issued Nov. 25, 1980 are disclosed mode converters particularly for converting linearly polarized waves into positively and negatively azimuthally phase-shifted waves. However in neither of these Patents is there a disclosure of TM.sub.0 to TE.sub.0 wave mode converters. U.S. Pat. No. 3,283,262 issued Nov. 1, 1966 discloses optical lasers operating in the TM.sub.on modes by means of a so-called Brewster cone which is a dielectric conical interface having a half cone angle equal to the 90.degree. complement of an angle having a tangent equal to the ratio of the two indicies of refraction of a media on two sides of an interface. The TM.sub.on mode waves pass through said interface without reflection while the other modes are partially reflected.
Yasuto Mushiake et al., in an article entitled "Generators of Radially Polarized Optical Beam Mode by Laser Oscillation" issued in Proc. IEEE, Vol. 9, September 1972, pages 1107-1109, have disclosed a laser cavity resonator having a subresonator defined by a conical glass substrate interface coated with a conical dielectric thin film. Such a laser radiates in a radially polarized mode, that is a TM.sub.0 mode.